What actually happens when a ship runs out of fuel?

[Woas]

As the topic implies, I've gone through the core rulebook and there are plenty of rules about the cost of fuel, refining fuel, where to obtain fuel, variant fuels, fuel requirements per 2 weeks of operation...

I don't see a paragraph about what happens when a ship runs out of fuel though. Would it be assumed most ships have emergency power cells or chemical battery backups that could work for a couple hours just for a distress signal? I'm no nuclear engineer, does starving a fusion reactor cause problems?

Anyone know where the information is listed or have any of their own thoughts on the subject?

 

[EDG]

As I've said (repeatedly), a fusion reactor realistically won't run out of fuel. Even if a single ton of hydrogen is left on board, that'll be enough to run it for years (if not decades).

Since M-drives run on reactor power, they also won't run out given the above.

The only thing that really uses up fuel at a rapid rate is the jump drive. And if you run out of jump fuel all that means is that you can't jump.

 

[alex_greene]

If the ship emerged out of Jump with no fuel left in its tanks, there'd be enough hydrogen left in storage to keep the drives and power plant running long enough to get it to a planet with suitable hydrographics or a gas giant for wilderness refuelling. Even running on batteries, the ship has its entry velocity from the moment it entered the system, and the ship can use thrusters to get it into a standard orbit. It's not as if the ship's going to just hang there, stranded in space.

Finally, if the ship has an auxiliary vehicle, the crew can drain it of its fuel, whether it's a Ship's Boat, launch, pinnace or even ATV or Air/Raft.

As my learned colleague stated, a ship's crew need never really worry about a vessel being stranded, even if it is literally running on fumes.

 

[Gee4orce]

As I've said (repeatedly), a fusion reactor realistically won't run out of fuel. Even if a single ton of hydrogen is left on board, that'll be enough to run it for years (if not decades).

Since M-drives run on reactor power, they also won't run out given the above.

Ok- but that's not very exciting. Let's change the questions to "what happens of the reactor is faulty or damaged, and has to be shut down" ?

This is mentioned in the combat section - taking out the reactor also disables energy weapons and M drive. What about life support (I can't remember) ? Presumably there's some level of redundancy or backup that provides heat and clean air, at least for a while ?

All ships IMTU have emergency low berths, so every body has at least a chance of survival, should the brown stuff hit the air circulation unit. Think Ripley in Aliens.

 

[alex_greene]

High Guard has the option of the backup power plant and chemical batteries and, of course, solar panels and a solar sail for propulsion.

Using solar panels, a ship can maintain basic life support for weeks, manoeuvring only with solar sails and using neither energy weapons nor active sensors, providing the ship isn't too far out from the star for solar energy to be viable.

Failing that, they might as well keep an exercise bike wired up to a dynamo, so that if the rubber band breaks they can still give the Engineer a job to do, and failing even that they might have to ask the passengers to get out and push.

 

[rust]

...and failing even that they might have to ask the passengers to get out and push.

A prudent captain probably would have some well trained reindeers sto-
red in his ship's emergency low berths, and a nice red vacc suit with whi-
te fur lining in his wardrobe ... 8)

 

[alex_greene]

But that's only a seasonal suit. The rest of the time, he'll have to wear his usual gold spandex and moon boots, and ...

oh, I give up. No, the ship will never end up stranded like Serenity in the Firefly episode "Out of Gas," unless you, as Referee, decide to punish the characters by stranding them as an act of fiat.

And nine times out of ten, "stranded" means "crashed planetside," rarely "drifting in space."

 

[GJD]

As I've said (repeatedly), a fusion reactor realistically won't run out of fuel. Even if a single ton of hydrogen is left on board, that'll be enough to run it for years (if not decades).

That's a rather sweeping statement. It rather depends on what hydrogen you have and what else is drawing power. Granted, the actual running costs of a fusion reactor seem to be low, they are also choosy about what they use. Deutirium and Tritium are rather rare.

G.

 

[Stofsk]

But that's only a seasonal suit. The rest of the time, he'll have to wear his usual gold spandex and moon boots, and ...

oh, I give up. No, the ship will never end up stranded like Serenity in the Firefly episode "Out of Gas," unless you, as Referee, decide to punish the characters by stranding them as an act of fiat.

And nine times out of ten, "stranded" means "crashed planetside," rarely "drifting in space."

I thought that Serenity was stranded because of some engine malfunction, not due to lack of fuel. But it's been awhile since I saw it last. I do remember though that the passerby ship which came to Serenity's aid, and then attempted to hijack the ship, came with some doohickey needed to install into the ship's engine.

Out of Gas was one of my favourite episodes of Firefly. Damn I wish that show hadn't been cancelled.

 

[alex_greene]

Serenity unable to change course, I could understand. Even spinning end over end around its centre of gravity in a flat spin.

But just hanging there in space with no forward momentum ... no. If Serenity had been pursuing an arc, it would be spinning off at a tangent the moment motive power cut out from the engine to provide acceleration. The only force applying to the ship, at that point, would be gravity, so it more or less would be proceeding along on a straight line (or close enough to one as to make no never mind).

But it wouldn't just park in one spot like a dead deep sea diver with neutral buoyancy floating in mid-ocean, waiting for the sharks to arrive.

Gaah. Too much adherence to physics over plot. I need 10 fl oz of decaff, stat.

 

[Stofsk]

I know what you mean. This is the show which seriously expected us to believe that firearms can't be fired in a vacuum, so their solution was to fire the rifle from inside a pressurised vacc-suit.

I loved the show, but sometimes it could be... very strange.

 

[Woas]

But by the rules it states that the power plant eats so many dTons of fuel per 2 weeks of operation. So I'm not really concerned about 'real world' answers. I mean I realize nuclear power plants work completely different and all, and appreciate the advice but we've been going by the book thus far, I really have no reason to change how it all works now.

So for example during ship combat, a hit results in a fuel leak (pg. 151) that causes 1d6 tons of fuel per hour to be lost. The damage can be patched back together after 1d6 hours of EVA work (pg. 143) but will eventually break down within 1d6 hours.

Assume the worst case scenario where a ship has just completely run out of fuel. Perhaps a hit from combat was on Fuel so they are leaking it badly and are far out in the system. Or worse, leaked during a jump or something. What happens? What systems shut down? What are the crews options?

 

[EDG]

That's a rather sweeping statement. It rather depends on what hydrogen you have and what else is drawing power. Granted, the actual running costs of a fusion reactor seem to be low, they are also choosy about what they use. Deutirium and Tritium are rather rare.

It's a rather accurate statement, actually . See discussion here for details: http://forums.sjgames.com/showthread.php?t=44453

And presumably when it says "liquid hydrogen" it really means liquid hydrogen of whatever the right isotopes are that you use for nuclear fusion - otherwise all that fuel isn't much use. That's what onboard processing is for.

 

[EDG]

But by the rules it states that the power plant eats so many dTons of fuel per 2 weeks of operation. So I'm not really concerned about 'real world' answers. I mean I realize nuclear power plants work completely different and all, and appreciate the advice but we've been going by the book thus far, I really have no reason to change how it all works now.

If you're not interested in our "own thoughts on the subject" then why did you ask for them at the end of your initial post?

 

[rust]

What happens? What systems shut down? What are the crews options?

In my setting a damaged reactor would mean that the energy banks of
the ship would take over and provide enough power to keep the life sup-
port system, the passive sensors and the communicators going for a mi-
nimum of 12 hours and a maximum of 72 hours, depending on the ship's
type.

If the crew is unable to repair the reactor or improvise some other po-
wer source within this time period, all they have left are the ship's small
craft (if any are carried) and the vacc suits, and perhaps the low berths
(most ships in my setting do not have low berths).

And after that, well ... back to character generation ... :twisted:

 

[atpollard]

Assume the worst case scenario where a ship has just completely run out of fuel. What happens? What systems shut down? What are the crews options?

Fusion reactors:
Starved of fuel just stop producing power (like a car running out of gas). In general, reactors that run out of coolant, have safety systems that shut them down.

Life Support - Food and Water:
Even without pumps running (which use lots of energy) the inconvenience of no working refreshers is not life threatening. I suggest that rations can be eaten uncooked and water obtained directly from the holding tanks with little difficulty.

Life Support - Air:
The air circulation system is critical and air fans draw far less power than water pumps. Most modern scrubbers (remove CO2) will continue to function for hours or days before needing recharge (steam cleaning of the catalyst to remove carbon deposits). I suggest that it would be reasonable for such a vital system to include at least 24 hours of integral emergency power. Beyond that, I suggest that some sort of mechanical (hand powered) backup should be standard.

Life Support - Heat:
This one is less cut and dry. The heat exchange system is a power hog in the real world (compressing gases into liquids is energy intensive) so this system may not function on emergency power. Space is a good insulator, so any ship past the habitable zone of a star should cool off slowly until everyone freezes. However, the cooling may not start until all of the power is out since all electric equipment (and human bodies) generate lots of heat.
Being too close to a star (closer than the habitable zone) will very quickly become a problem since the ship will become hotter and hotter with no way to cool off. Skylab dealt with the problem by erecting a tent to shade the station - think emergency crew EVA and 'how many blankets do we have?'

Crew options:
The Jump Drive has power capacitors that store a charge to start it up - those might be tapped for emergency power.

Solar winds contain hydrogen which may or may not be collectable and usefull for providing a trickle of power.

 

[BP]

From the TMB (Core pg 107):
".. power both the jump drive and the power plant..."
".. amounts listed will power the ship for two weeks..."

Little is said about what happens then, except (Core pg 142):
"Suffocation... with power..six months at a stretch...without... two weeks at most"

Of course, since unrefined fuel is allowed (at a risk), why not just pee in the tanks!

Seriously, being left undefined is probably best - make it match your needs - if you need no power to mean no comms/lighting/etc. then go for it. Personnally, I would likely go with no or emergency manuever for x period and all powered systems shut down or standby - with some emergency lighting/airlocks/bay doors and manual overrides for decompression...

 

[The Chef]

But that's only a seasonal suit. The rest of the time, he'll have to wear his usual gold spandex and moon boots, and ...

oh, I give up. No, the ship will never end up stranded like Serenity in the Firefly episode "Out of Gas," unless you, as Referee, decide to punish the characters by stranding them as an act of fiat.

And nine times out of ten, "stranded" means "crashed planetside," rarely "drifting in space."

I thought that Serenity was stranded because of some engine malfunction, not due to lack of fuel. But it's been awhile since I saw it last. I do remember though that the passerby ship which came to Serenity's aid, and then attempted to hijack the ship, came with some doohickey needed to install into the ship's engine.

Out of Gas was one of my favourite episodes of Firefly. Damn I wish that show hadn't been cancelled.

The lack of gas refers to air, the life support system crashed once the engine stopped turning and most of the air was burnt off in the fire.

also guns firing in space. Before EDG pointed it out on a different thread, i would have said that no guns work in space (i now know this is wrong). Now i am reasonable at science, and love science fiction, and i would have been shouting at the screen if they hadn't used an air source to shoot an automatic weapon in space. i think for the vast majority of people the solution to use a space suit covered gun worked... and i think it would have pushed my sense of disbelief to far if they hadn't. all science fiction is for the masses, whether they are hillbillies like me or astrophysisists, like most of the people on these boards.

back on thread.

i would have the non critical systems shut down first, followed by the critical systems. of course i would have more of a gas leak/venting atmo failure rather than a fuel problem, as they are slightly more immediate issues.

chef

 

[GypsyComet]

Assuming a ship can control its heat dispersal, you're not likely to freeze for a while. The amount of waste heat in a ship is amazing.

The air will start to go stale at some point. How soon will depend on how much terrarium space the crew keeps in their staterooms, whether or not there are a few good batteries around to keep some lights on, and the amount of living space vs the number of people in it.

There is also enough latent moisture in a ship to potentially run a small fuel cell. Since a minimal fuel purification system already has all the parts necessary and just needs a little plumbing work (maybe borrowing a heat exchanger from the not-currently-running fusion plant), you may be able to keep a ship lit with a few kilowatts for a long time.

What's in the cargo bay, Macgyver?

If you're in a system with people and space travel, the chances of being spotted and rescued before you die are pretty good. If you ran out of gas near a gas giant, you almost don't need to dive the GG to get enough fuel, especially if its got ice rings.

 

[Klaus Kipling]

But just hanging there in space with no forward momentum ... no.

There was nothing in that ep to say it was 'stationary'.


Anyway, stationary is impossible in an absolute sense. Stationary relative to what...?

That's why the meson comm is more or less useless unless both parties are on a planet, but that's another thread....